The present invention relates to a seals, sealing elements, gaskets, stoppers and like structures and elements and their use for securing, closing and/or preventing the passage of substances. It further relates to devices and methods for administering medical or medicinal substances in doses, for example, injection and infusion devices, syringes, injection pens, etc. More particularly, it relates to a seal or sealing element for use in an injection device.
An embodiment of a known injection device is described in WO 03/053499, wherein FIG. 5 shows a rear portion of the injection device (a pen) in a longitudinal section. A piston rod K advances a piston (not shown) along the longitudinal axis L in the advancing direction (to the left in FIG. 5) towards a reservoir outlet (not shown), wherein the extent of the shift by the piston rod K is defined by rotating the setting element E and can be triggered by pressing the setting element E. In order to show a user which dosage he has set by rotating the setting element E, an indicating element A is provided on which the amount of a dosage set is shown, wherein the dosage set is ascertained on the basis of the movement of contact elements 10 which are pressed by one or more cam discs 11 which are also rotated by a rotational movement of the setting element E. If the cam discs 11 are suitably arranged, the succession of pressing and releasing the contact elements 10 by the cam discs 11 enables a determination as to how much the setting element E has been rotated, in order to indicate, on the indicating element A, a dosage or amount of active agent to be dispensed, set by the rotation.
However, a small amount of the substance to be dispensed by the device can penetrate, for example through openings provided for the contact elements 10, into the so-called E-module M or into the circuit or circuit board provided for evaluating the movement of the contact elements 10, and can damage the electronics. Equally, the electronics or the battery provided for operating the electronics can be compromised if such a device is stored in a refrigerator in order to ensure that the substance to be dispensed is optimally stored, wherein moisture can easily reach the electronics if the air is cooled and compressed.